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PI53257: CPU INCREASE USING CPSM AS DISTRIBUTED ROUTING PROGRAM

A fix is available

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APAR status

  • Closed as program error.

Error description

  • You use CPSM as your distributed routing program. The CPU use
    for each transaction in your CICS region slowly increases over
    time if the CICS region stays up for long periods. When you
    recycle the region, CPU use per transaction goes back to
    'normal' but as the region stays up longer, the CPU use per
    transaction begins to grow again.
    .
    If you are using a performance monitor software that samples
    which program the region spends more and more of its time in,
    you will find that the monitoring software reports that CICS
    spends more of its time in CPSM module EYU9XC01. If the CICS
    and CPSM releases are not the same in the region, the CPSM
    module name may be CJ*9XC01, where '*' may be A, B, C, D, etc.
    .
    The problem occurs if your CPSM Workload is configured with
    AFFINITIES. The increase in CPU occurs because UOW Affinities
    are being orphaned when tasks terminate. The chain of orphaned
    UOWs grows larger and larger the longer the region remains up,
    and CICS spends more and more time manipulating this chain.
    .
    You can verify that the chain is growing by using the CPSM Web
    User Interface, WUI, and navigating to the WLMATAFF view,
    "Active workload transaction group affinities" view. That view
    has a hotlink which takes you to the Active Tasks view for the
    UOW, but that Active Tasks view is empty, because the tasks
    have terminated long ago. The list of affinities continues to
    grow the longer the region remains up.
    .
    The problem is that under certain circumstances, CICS is not
    calling CPSM at task termination, so CPSM does not know that
    the UOW is to be cleaned up.
    .
    Additional Symptom(s) Search Keyword(s): KIXREVSVR
    

Local fix

  • Cycle the region to temporarily return CPU use to normal
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All CICS Users.                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: When running a CICS WS-AT transaction   *
    *                      under a CPSM workload, CPU usage        *
    *                      increases until region is recycled.     *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    When running CICS WS-AT transactions under CPSM which is defined
    in a workload the UOW affinity control blocks keep increasing
    until the CICS region is recycled. The amount of CPU being used
    also increases as the UOW affinity control blocks increase. The
    UOW affinity control blocks are not being cleared up because
    when COMMIT or ROLLBACK are issued, code to notify CPSM of the
    end of UOW is not issued.  This leaves the UOW affinity control
    blocks allocated until the region is recycled.
    
    Keyword(s): WSAT
    

Problem conclusion

  • DFHRMOT has been changed to issue the required end of UOW notify
    call to CPSM for COMMIT and BACKOUT operations.
    

Temporary fix

  • FIX AVAILABLE BY PTF ONLY
    

Comments

APAR Information

  • APAR number

    PI53257

  • Reported component name

    CICS TS Z/OS V4

  • Reported component ID

    5655S9700

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2015-11-27

  • Closed date

    2016-03-18

  • Last modified date

    2016-04-05

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

    PI55929 UI36334

Modules/Macros

  • DFHRMOT
    

Fix information

  • Fixed component name

    CICS TS Z/OS V4

  • Fixed component ID

    5655S9700

Applicable component levels

  • R700 PSY UI36334

       UP16/03/24 P F603

Fix is available

  • Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

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Document Information

Modified date:
05 April 2016